<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .video {
            display: block;
            width: 448px;
            height: 252px;
            background: url(images/tudou.jpg);
            margin: 100px auto;
        }
        .cover {
            display: none;
            width: 448px;
            height: 252px;
            background: rgba(0, 0, 0, 0.3) url(images/arr.png) no-repeat center;
        }
        .video:hover .cover {
            display: block;
        }
    </style>
</head>
<body>
    <a href="#" class="video">
        <div class="cover"></div>
    </a>
</body>
</html>